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US 4,882,484 AGranted
Method of mass analyzing a sample by use of a quistor
AssigneeThe United States of America as represented by the Secretary of the Army
InventorsJochen Franzen, Reemt-Holger Gabling, Gerhard Heinen, Gerhard Weiss
Life of this patent
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Abstract
In a quadrupole ion store (QUISTOR), a sample is analyzed by increasing the mplitude of the harmonic, or "secular", oscillations of selected stably trapped ions so that they leave the trapping field. In a preferred embodiment, deviations from the ideal electrode geometry are incorporated into the QUISTOR to produce resonance phenomena between the r and z secular oscillations, thereby increasing the amplitude of oscillations in the z direction.
Claims10
The method of mass analyzing a sample which comprises the steps of:
- defining a three-dimensional electrical quadrupole storage field in which sample ions over the entire mass range of interest can be simultaneously trapped;
- introducing or creating sample ions into the quadrupole field whereby ions within the mass range of interest are simultaneously trapped and perform ion-mass specific secular movements;
- superimposing an exciting RF field with a frequency different from that of the storage RF field;
- changing the superimposed fields so that simultaneously and stably trapped ions of consecutive masses encounter a resonance of their secular movements with the exciting RF field, take up energy, increase thereby the secular movement amplitudes, and leave the trapping field;
- detecting the ions of sequential masses as they leave the trapping field;
- and
- providing an output signal indicative of the ion mass.
4 more elements
Dependencies are inferred from the claim text.